1. Field of the Invention
The present invention relates to a circulatory-organ evaluating apparatus which evaluates a circulatory organ of a living subject.
2. Related Art Statement
The dynamic function of circulatory organ of a living person is primarily defined by the pumping function of the person's heart, and also is influenced by the degree of contraction or dilation of walls of blood vessels (e.g., the degree of hardness of arteries) or the diameter of blood vessels.
Therefore, the dynamic function of circulatory organ is evaluated by measuring, e.g., the person's blood pressure. If the person is diagnosed with hypertension, the person will undergo a medical treatment such as administration of antihypertensive drug. In addition, since the blood pressure is influenced by the degree of hardness of arteries, there will be some cases where pulse-wave-velocity-related information that is related to a velocity at which a pulse wave propagates between the person's two portions is obtained so as to evaluate the degree of hardness of arteries as well. Those evaluations may be made by, e.g., an apparatus disclosed by Japanese Patent Document No. 9-140679 or its corresponding U.S. Pat. No. 5,743,856.
Meanwhile, there are some indexes used for evaluating the circulatory organ of living person. Those indexes include, in addition to blood pressure and pulse-wave-velocity-related information, augmentation index, AI. The augmentation index indicates a proportion of a reflected-wave component of a pulse wave to an incident-wave component of the same. In order to accurately evaluate the circulatory organ, it is preferred to simultaneously measure augmentation index in addition to blood pressure and pulse-wave-velocity-related information, because the increased number of physical parameters obtained from the person can be used to evaluate the circulatory organ.
However, in the case where the circulatory organ is evaluated by measuring the three indexes, i.e., blood pressure, pulse-wave-velocity-related information, and augmentation index, if respective measured values of the three indexes are just displayed, it is difficult to speculate how pulse-wave-velocity-related information or augmentation index influences blood pressure, or conversely if blood pressure influences pulse-wave-velocity-related information or augmentation index. Thus, there are some cases where it is difficult to evaluate the circulatory organ if the three measured values are just displayed. In particular, in the case where a patient is informed of a therapy to be taken or of therapeutic effects, it is difficult for the patient to evaluate the circulatory organ based on only the measured values.